The best CMS software knows they are only made better by expanding their basic offerings. For true customization and full ability to meet your unique needs, there should be some level of add-on you can integrate. Each website is going to be a little different, and you’re going to have specific functionality needs, so having access to apps and extensions that make those needs possible is key.
If you have members of your target marketing following you on social media, publish a post where you ask them to reveal any specific questions or challenges they have about your course topic. Just like with an email, you could share a link to a survey as an alternative to responding to you publicly (this might be the better option depending on the nature of your course topic).
If you don’t have a design muscle in your body, you might experience some difficulties making a Squarespace site look good (due to the platform’s reliance on good stock imagery to be part of your site’s final look). Also, Squarespace offers a good range of features from the get-go, but above that, there’s not much you can do when there’s a feature missing. Just like with Wix, if you want a site that can grow alongside your business, this might not be quite the solution you’re looking for.